U.S. patent application number 12/814480 was filed with the patent office on 2011-02-10 for scanning device and scanning method thereof.
This patent application is currently assigned to Qisda (SuZhou) Co., ltd. Invention is credited to Yong-Xiang Yi.
Application Number | 20110032580 12/814480 |
Document ID | / |
Family ID | 41576112 |
Filed Date | 2011-02-10 |
United States Patent
Application |
20110032580 |
Kind Code |
A1 |
Yi; Yong-Xiang |
February 10, 2011 |
SCANNING DEVICE AND SCANNING METHOD THEREOF
Abstract
A scanning device and a scanning method thereof are provided.
The scanning device includes a scanning group, a paper-feed roller
and a calibration portion. The scanning group includes a line light
source generating module and a scanning module. The line light
source generating module includes a point light source, a
light-guiding plate and a casing. The light emitted by the point
light source along a first direction is converted into a line light
source through a light-guiding plate disposed in the casing. The
light emitted by the line light source along a second direction is
emitted from an opening of the casing. The scanning module, along
the first direction, includes a scan document region and a
calibration region. The light reflected through the to-be-scanned
document is received in the scan document region. The calibration
portion disposed on the casing or the paper-feed roller corresponds
to the calibration region.
Inventors: |
Yi; Yong-Xiang; (SuZhou
City, CN) |
Correspondence
Address: |
COVENANT IP CONSULTING CO.
P.O. BOX 34-306 TAIPEI CITY
TAIPEI
10499
TW
|
Assignee: |
Qisda (SuZhou) Co., ltd
Suzhou
CN
|
Family ID: |
41576112 |
Appl. No.: |
12/814480 |
Filed: |
June 13, 2010 |
Current U.S.
Class: |
358/406 |
Current CPC
Class: |
H04N 1/0005 20130101;
H04N 1/00013 20130101; H04N 1/00023 20130101; H04N 1/00087
20130101; H04N 1/125 20130101; H04N 2201/03141 20130101; H04N
1/00034 20130101; H04N 1/00055 20130101; H04N 1/00002 20130101;
H04N 1/00063 20130101; H04N 1/02835 20130101; H04N 2201/0081
20130101; H04N 2201/03112 20130101; H04N 2201/0096 20130101; H04N
1/00045 20130101; H04N 1/1215 20130101; H04N 2201/03125 20130101;
H04N 2201/03145 20130101; H04N 1/193 20130101 |
Class at
Publication: |
358/406 |
International
Class: |
H04N 1/00 20060101
H04N001/00 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 7, 2009 |
CN |
200910163864.4 |
Claims
1. A scanning device, comprising: a scanning group comprising a
line light source generating module and a scanning module, wherein
the line light source generating module comprises a point light
source, a light-guiding plate and a casing, a light emitted by the
point light source along a first direction is converted into a line
light source through the light-guiding plate disposed in the
casing, the light emitted by the line light source along a second
direction is emitted from an opening of the casing, the scanning
module comprises a scan document region and a calibration region
along the first direction, and the light reflected through a
to-be-scanned document is received in the scan document region; a
paper-feed roller disposed adjacent to the scanning group for
driving the to-be-scanned document; a calibration portion disposed
on the casing or the paper-feed roller, wherein the calibration
portion corresponds to the calibration region of the scanning
module and the reflected light is received in the calibration
region through the calibration portion.
2. The scanning device according to claim 1, wherein the
calibration portion is a reflection layer disposed around the
paper-feed roller.
3. The scanning device according to claim 1, wherein the
calibration portion and the casing are integrally formed in one
piece.
4. The scanning device according to claim 1, further comprising: a
light source control circuit for controlling the illumination
parameters of the line light source generating module; a
calibration control system electrically connected to the scanning
module and the light source control circuit for adjusting the light
source control circuit according to the signal feedbacked from the
calibration region.
5. The scanning device according to claim 1, wherein the point
light source is red/green/blue (RGB) light emitting diodes
(LEDs).
6. The scanning device according to claim 1, wherein the scanning
module comprises a cylindrical lens array and a CIS array, and the
reflected light is received by the CIS array through the
cylindrical lens array.
7. A scanning method, comprising the following steps: A. providing
a calibration portion corresponding to a calibration region of a
scanning module; B. pre-scanning a document, wherein a light
emitted by a light source is reflected through the calibration
portion and received in the calibration region, and, at the same
time, a first brightness signal is generated; C. comparing the
first brightness signal to a pre-determined signal; D. adjusting
the light source and repeating the step B if a difference between
the first brightness signal and the pre-determined signal is
greater than a reference value; E. formally scanning the document
if the difference between the first brightness signal and the
pre-determined signal is smaller than or equal to the reference
value.
8. The scanning method according to claim 7, wherein the scanning
module further comprises a scan document region along the first
direction, and the light emitted by the light source is reflected
through a to-be-scanned document and received in the scan document
region.
9. The scanning method according to claim 7, wherein before the
step B, a brightness or an exposure time of the light source is
pre-determined.
10. The scanning method according to claim 7, wherein in the step
D, an exposure time of the light source is increased or decreased.
Description
[0001] This application claims the benefit of People's Republic of
China application Serial No. 200910163864.4, filed Aug. 7, 2009,
the subject matter of which is incorporated herein by
reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The invention relates in general to a scanning device and a
scanning method thereof, and more particularly to a scanning device
with automatic calibration of brightness and colors and a scanning
method thereof.
[0004] 2. Description of the Related Art
[0005] The portable scanner normally adopts the contact image
sensor (CIS) as an image collecting element, and the color CIS
normally adopts the RGB (red/green/blue) light emitting diodes
(LEDs) as a light source for illumination. Inside the portable
scanner, electronic elements such as motor, driving circuit board
and LED light source generate heat during operation. The
temperature inside the scanning device changes accordingly with the
change in the temperature of the working environment, and such
change leads to the change in the LED brightness of the CIS and
subsequently changes the brightness of the scan image. Since the
RGB LEDs do not change with the temperature change in a uniform
manner, the RGB colors of the scan image have respective changes
which are different from one another. And the difference in the
change of the RGB colors is reflected in the scan image as color
aberration.
[0006] A generally known solution to resolve the problem of color
aberration is to perform color calibration using a particular white
document as a standard document before the scanning process is
performed. In general, the standard document is fixed in the
scanning device and the length of the standard document is slightly
larger than that of the CIS. The CIS reads the standard document
and adjusts the exposure time of the LED according to the
comparison between the standard document and the pre-determined
brightness value of image so as to control the brightness of the
scan image. Besides, the brightness data of the standard document
obtained by the CIS can be used for calibrating the brightness
difference among the pixels so that the brightness of the obtained
image is uniform. The above method is normally adapted in the
flat-bed scanner. Due to the restrictions in the design, the
portable scanner or the paper-feed scanner normally does not
provide the standard document that is fixed in the scanning device.
Instead, the portable scanner or the paper-feed scanner provides an
extra standard document for the user to decide when to perform
calibration. Unlike the flat-bed scanner, the portable scanner or
the paper-feed scanner cannot perform at anytime.
[0007] However, a problem arises. That is, after a scanner has
worked for a period of time, or the environmental temperature of
the scanner has changed, the brightness of the LED of the CIS will
change due to the change in the environmental temperature, and such
brightness change will make the brightness of the scanned image
change or even result in color aberration.
SUMMARY OF THE INVENTION
[0008] The invention is provided to resolve the above technical
problems. The light emitted from the LED light source of a CIS is
reflected to a part of the sensing elements of the CIS through a
calibration portion. The intensity of the reflected light is
examined by the part of the sensing elements in real time, and the
brightness of the LED light source is feedbacked to a control
system which accordingly adjusts the brightness of the LED light
source by controlling relevant circuits of the LED light
source.
[0009] The scanning device of the invention includes a scanning
group, a f paper-feed roller and a calibration portion. The
scanning group includes a line light source generating module and a
scanning module. The line light source generating module includes a
point light source, a light-guiding plate and a casing. The light
emitted by the point light source along a first direction is
converted into a line light source through a light-guiding plate
disposed in the casing. The light emitted by the line light source
along a second direction is emitted from an opening of the casing.
The scanning module includes a scan document region and a
calibration region along the first direction. The light reflected
through the to-be-scanned document is received in the scan document
region. The paper-feed roller is disposed adjacent to the scanning
group. The calibration portion is disposed on the casing or the
paper-feed roller and corresponds to the calibration region of the
scanning module, and the light reflected through the calibration
portion is received in the calibration region.
[0010] According to the scanning device of the invention, the
calibration portion is a reflection layer disposed around the
paper-feed roller.
[0011] According to the scanning device of the invention, the
calibration portion and the casing are integrally formed in one
piece.
[0012] The scanning device of the invention further includes a
light source control circuit and a calibration control system. The
light source control circuit is for controlling the illumination
parameters of the line light source generating module. The
calibration control system is electrically connected to the
scanning module and the light source control circuit for adjusting
the light source control circuit according to the signal feedbacked
from the calibration region.
[0013] According to the scanning device of the invention, the point
light source is RGB light emitting diodes.
[0014] According to the scanning device of the invention, the
scanning module includes a cylindrical lens array and a contact
image sensor (CIS) array, and the reflected light is received by
the CIS array through the cylindrical lens array.
[0015] The scanning method of the invention includes the following
steps. In step A, a calibration portion corresponding to a
calibration region of a scanning module is provided. In step B, a
document is pre-scanned, the light emitted by a light source is
reflected through the calibration portion and received in the
calibration region, and, at the same time, a first brightness
signal is generated. In step C, the first brightness signal is
compared to a pre-determined signal. In step D, if the difference
between the first brightness signal and the pre-determined signal
is greater than a reference value, then the light source is
adjusted, and the step B is repeated. In step E, if the difference
between the first brightness signal and the pre-determined signal
is smaller than or equal to the reference value, then a document is
formally scanned.
[0016] According to the scanning method of the invention, the
scanning module, along the first direction, further includes a scan
document region, and the light emitted by the light source is
reflected through the to-be-scanned document and received in the
scan document region.
[0017] According to the scanning method of the invention, before
the step B, the brightness or an exposure time of the light source
is pre-determined.
[0018] According to the scanning method of the invention, in the
step D, an exposure time of the light source is increased or
decreased.
[0019] To resolve the problems such as color aberration and
brightness change, which occur to the portable scanner due to
temperature change, the invention provides a scanning device with
automatic calibration of brightness and colors, so that the user no
more need to perform manual calibration after the occurrence of
brightness change or color aberration. The invention provides the
user with great convenience.
[0020] The invention will become apparent from the following
detailed description of the preferred but non-limiting embodiments.
The following description is made with reference to the
accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] FIG. 1 shows a structural diagram of a scanning device
according to an embodiment of the invention;
[0022] FIG. 2 shows a position diagram of a calibration portion
according to an embodiment of the invention;
[0023] FIG. 3 shows a system diagram of a scanning device according
to an embodiment of the invention;
[0024] FIG. 4 shows a structural diagram of a scanning device
according to another embodiment of the invention;
[0025] FIG. 5 shows a position diagram of a calibration portion
according to another embodiment of the invention;
[0026] FIG. 6 shows a scan document region and a calibration region
according to another embodiment of the invention;
[0027] FIG. 7A and FIG. 7B respectively show a structural diagram
of a scanning device according to yet another embodiment of the
invention;
[0028] FIG. 8 shows a flowchart of a scanning method according to
an embodiment of the invention; and
[0029] FIG. 9 shows a flowchart of a scanning method according to
another embodiment of the invention.
DETAILED DESCRIPTION OF THE INVENTION
[0030] Detailed descriptions of the objects, structures, features
and functions of the invention are disclosed in a number of
embodiments below.
[0031] Referring to FIG. 1 and FIG. 2. FIG. 1 shows a structural
diagram of a scanning device 1 according to an embodiment of the
invention. FIG. 2 shows a position diagram of a calibration portion
13 according to an embodiment of the invention. The scanning device
1 includes a scanning group 10, a paper-feed roller 11 and a
calibration portion 13. The scanning group 10 includes a line light
source generating module 14 and a scanning module 15. The line
light source generating module 14 includes a point light source
101, a light-guiding plate 102 and a casing 103. The light emitted
by the point light source 101 along a first direction X is
converted into a line light source through the light-guiding plate
102. The light-guiding plate 102 is disposed in the casing 103. The
light emitted by the line light source along a second direction Y
is emitted from the opening of the casing 103. The scanning module
15, along the first direction X, includes a scan document region
151 and a calibration region 152. The light reflected through the
to-be-scanned document 19 is received in the scan document region
151. The paper-feed roller 11 is disposed adjacent to the scanning
group 10 for driving the to-be-scanned document 19. The calibration
portion 13 is disposed on the paper-feed roller 11 and corresponds
to the calibration region 152 of the scanning module 15. The light
reflected through the calibration portion 13 is received in the
calibration region 152.
[0032] In an embodiment, the calibration portion 13 is a reflection
layer disposed around the paper-feed roller 11. In practical
application, the calibration portion 13 has a white reflective
coating layer. The point light source 101 is red/green/blue (RGB)
light emitting diodes (LEDs). Preferably, the first direction X is
perpendicular to the second direction Y.
[0033] In an embodiment, the scanning module 15 includes a
cylindrical lens array 106 and a contact image sensor (CIS) array
105. The reflected light is received by the CIS array 105 through
the cylindrical lens array 106. The CIS array 105, along the first
direction X, includes a scan document region 151 and a calibration
region 152. The light reflected through the to-be-scanned document
19 is received in the scan document region 15 by a part of the
sensing elements, and the light reflected through the calibration
portion 13 is received in the calibration region 152 by the other
part of the sensing elements.
[0034] Also referring to FIG. 3, a system diagram of a scanning
device 1 according to an embodiment of the invention is shown. The
scanning device 1 further includes a light source control circuit
16 and a calibration control system 17. The light source control
circuit 16 is for controlling the illumination parameters of the
line light source generating module 14. The calibration control
system 17 is electrically connected to the scanning module 15 and
the light source control circuit 16 for adjusting the light source
control circuit 16 according to the signal feedbacked from the
calibration region 152.
[0035] Continue to refer to FIG. 4 and FIG. 5. FIG. 4 shows a
structural diagram of a scanning device 4 according to another
embodiment of the invention. FIG. 5 shows a position diagram of a
calibration portion 43 according to another embodiment of the
invention. The scanning device 4 includes a scanning group 40 and a
calibration portion 43. The scanning group 40 includes a line light
source generating module 44 and a scanning module 45. The line
light source generating module 44 includes a point light source
401, a light-guiding plate 402 and a casing 403. The light emitted
by the point light source 401 along a first direction X is
converted into a line light source through the light-guiding plate
402 disposed in the casing 403. The light emitted by the line light
source along a second direction is emitted from the opening 404 of
the casing 403. The scanning module 45, along the first direction
X, includes a scan document region and a calibration region. The
light reflected through the to-be-scanned document is received in
the scan document region. The calibration portion 43 is disposed on
the casing 403 and corresponds to the calibration region of the
scanning module 45. The light reflected through the calibration
portion 43 is received in the calibration region.
[0036] In practical application, the calibration portion 43 and the
casing 403 are integrally formed in one piece. In the first
direction X, the length of the calibration portion 43 is far
smaller than that of the light-guiding plate 402. Thus, a part of
the light emitted from the line light source is reflected through
the calibration portion 43 and enters the calibration region of the
scanning module 45, and another part of the light is reflected
through the to-be-scanned document and enters the scan document
region of the scanning module 45. The point light source 401 is RGB
light emitting diodes, and is connected to the light source control
circuit.
[0037] In the embodiment, the scanning module 45 includes a
cylindrical lens array 406 and a CIS array 405. The light reflected
through the cylindrical lens array 406 is received by the CIS array
405. Referring to FIG. 6, a scan document region 451 and a
calibration region 452 according to another embodiment of the
invention are shown. The CIS array 405 of the scanning module,
along the first direction X, includes a scan document region 451
and a calibration region 452. The light reflected through the
to-be-scanned document is received in the scan document region 451
by a part of the sensing elements, and the light reflected through
the calibration portion is received in the calibration region 452
by another part of the sensing elements.
[0038] Apart from the above embodiments, the calibration portion is
disposed on the surface of the scanning group to realize the
real-time automatic feedback of the brightness of the light source.
Referring to FIG. 7A and FIG. 7B, two structural diagrams of a
scanning device according to yet another embodiment of the
invention are respectively shown. A reflector sheet 73 (the
calibration portion) is added to a part of the scannable region of
the scanning module 75. The reflector sheet 73 is fixed on the
scanning module 75, and does not interfere with the position of the
paper-feed roller 71. The light source brightness feedback signal
reflected through the reflector sheet 73 is received by a
corresponding part of the sensing elements of the scanning module
75.
[0039] Referring to FIG. 8, a flowchart of a scanning method
according to an embodiment of the invention is shown. The scanning
method of the invention includes the following steps. In step S61,
a calibration portion corresponding to the calibration region of
the scanning module is provided, wherein the scanning module, along
the first direction, further includes a scan document region, and a
light emitted by the light source is reflected through the
to-be-scanned document and received in the scan document region. In
step S62, a document is pre-scanned, the light emitted by the light
source is reflected through the calibration portion and received in
the calibration region, and, at the same time, a first brightness
signal is generated. In practical application, the first brightness
signal can be the average brightness of the signals received in the
calibration region. In step S63, the first brightness signal is
compared to a pre-determined signal. In practical application, the
pre-determined signal can be the average brightness of the signals
received in the calibration region when the scanning device is
initially calibrated. In step S64, if the difference between the
first brightness signal and the pre-determined signal is greater
than the reference value, then the light source is adjusted and the
step S62 is repeated. In step S65, if the difference between the
first brightness signal and the pre-determined signal is smaller
than or equal to the reference value, then the document is formally
scanned.
[0040] Referring to FIG. 9, a flowchart of a scanning method
according to another embodiment of the invention is shown. The
scanning method of the invention includes the following steps. In
S81, a calibration portion corresponding to the calibration region
of the scanning module is provided. The scanning module, along the
first direction, further includes a scan document region, and the
light emitted by the light source is reflected through the
to-be-scanned document and received in the scan document region. In
S82, the exposure time of the light source is pre-determined. In
S83, a document is pre-scanned, the light emitted by the light
source through the calibration portion is reflected and received in
the calibration region, and, at the same time, a first brightness
signal is generated. In S84, the first brightness signal is
compared to a pre-determined signal. S85, if the difference between
the first brightness signal and the pre-determined signal is
greater than the reference value d, then the exposure time of the
light source is increased or decreased and the step S83 is
repeated. In practical application, the first brightness signal can
be the average brightness Br of the signals received in the
calibration region, and the pre-determined signal can be the
average brightness Br0 of the signals received in the calibration
region when the scanning device is initially calibrated. If
Br-Br0>d, then the exposure time of the light source is
decreased. If Br0-Br>d, then the exposure time of the light
source is increased. In step S86, if the difference between the
first brightness signal and the pre-determined signal is smaller
than or equal to the reference value, that is, |Br-Br0|.ltoreq.d,
then the document is formally scanned. Besides, during the formal
scanning process, the step of performing a generally known image
processing algorithm can be included.
[0041] By adding the LED brightness feedback mechanism to the CIS
scanning device, the influence on the brightness of the LED of the
CIS which occurs due to the change in temperature or other factors
can be adjusted in real time. Through the calibration portion
disposed at one end of the CIS, during the scanning process, the
CIS output signal also includes a brightness signal of the
calibration portion. The brightness signal can be compared to the
signal calibrated for the first time so as to determine whether the
brightness of the CIS has changed or not. If the brightness has
changed, then relevant circuits of the LED are adjusted by the
control system so as to maintain the original brightness of the
CIS.
[0042] To resolve the problems such as color aberration and
brightness change, which occur to the portable scanner due to
temperature change, the invention provides a scanning device with
automatic calibration of brightness and colors, so that the user no
more need to perform manual calibration using a calibration card
after the occurrence of brightness change or color aberration. The
invention provides the user with great convenience.
[0043] While the invention has been described by way of example and
in terms of a preferred embodiment, it is to be understood that the
invention is not limited thereto. On the contrary, it is intended
to cover various modifications and similar arrangements and
procedures, and the scope of the appended claims therefore should
be accorded the broadest interpretation so as to encompass all such
modifications and similar arrangements and procedures.
* * * * *